1. Field of the Invention
The present invention relates generally to piano tuning and particularly to digital/electric just intonation tuning in real time.
2. Description of the Related Art
Pianos are impossible to be tuned harmonically. They are always slightly out of tune. Different approaches have been put forward but none have been able to make all the notes completely sound in tune at the same time. The presently used in the art tuning method (i.e., equal temperament) distributes the inharmonicity evenly throughout the musical scale making pianos sound always out of tune which can be heard in the form of beats when two or more notes are played.
While giving a solution to mechanical pianos is unpractical, if not impossible, a solution to this problem on digital/electric pianos is viable. By the use of a processor and a program with a set of logic instructions to determine, really fast (i.e., in the range of a few milliseconds) appropriate tones (i.e., frequencies), that would yield a harmonic ratio between keys being played, real time harmonic tuning of a digital/electric piano may be achieved.
Approaches for tuning a digital piano, including real time and just intonation tuning, are known in the art to overcome the out-of-tune problem. For example, applicant is aware of U.S. Pat. No. 5,501,130 issued on Mar. 26, 1996 to Gannon, et al., which describes an apparatus for adjusting the tuning of a musical instrument to cause the instrument to sound in just intonation while the instrument is being played. The apparatus comprises a data base in memory for storing an array of just intonation tone identifiers. The tone identifiers in the array are arranged by key, chordal root and tone according to just intonation relationships defined by the ratios of a scale selected by the musician. A selector unit is provided for enabling a musician to select a key and/or a chordal root, as a result of which a CPU retrieves from the array a set of tone identifiers in just intonation corresponding to the selected key or chordal root and transmits them to the sounding means of the instrument.
Applicant is further aware of U.S. Pat. No. 4,152,964 issued on May 8, 1979 to Waage, which describes a keyboard controlled just intonation computer for electronic organs which automatically responds to correct the larger tuning errors of equal temperament as each interval or chord is played. The logic circuit for this purpose has twelve inputs corresponding to the twelve notes of the chromatic scale. When the logic circuit is turned off the instrument remains tuned to equal temperament.
Applicant is also aware of U.S. Pat. No. 7,105,734 issued on Sep. 12, 2006 to Tucmandl, which describes the use of a sound sample library storage unit. In order to manage the sound samples stored in the above-mentioned storage unit, a bidirectional sound parameter storage unit is provided, which is bidirectional or multidirectional data-flow and data-exchange connected at least to the processor unit and to the sequencer. Each of the sound samples stored in the sound sample storage unit are assigned to said bidirectional sound parameter storage unit, which contains sound definition parameters enabling access to sound samples.
Applicant is also aware of U.S. Pat. No. 7,514,620 issued on Apr. 7, 2009 to Friedman, legal representative, which describes a method and apparatus for shifting pitches of audio signals to achieve desired pitch relationships between the audio signals. The audio signals may be in either a digital or analog format. One of the input audio signals is selected to be a reference signal. For each of the other audio signals, the pitch of the other audio signal is compared with the pitch of the reference signal to determine a relative pitch relationship. For each of the other signals, an adjustment is determined to bring the relationship to a desired pitch relationship. Based on the adjustment, the pitch of at least one of the audio signals is adjusted to achieve the desired pitch relationship between the audio signals. The desired pitch relationship between the pitch of the reference signal and the pitch of the audio signal other than the reference signal may be based on a just intonation.
Applicant is also aware of U.S. Pat. Appl. No. 20010037196 published on Nov. 1, 2001, which describes an apparatus for generating an additional sound signal on the basis of an input sound signal, which comprises: an input device adapted to receive control information for controlling a pitch of an additional sound; and a processor device coupled with the input device. The processor device is adapted to: obtain pitch information of the input sound signal; obtain scale note pitch information of an additional sound to be generated; determine a scale note pitch nearest to a pitch indicated by the pitch information of the input sound signal; modify the additional sound to be generated; and generate an additional sound signal with the modified pitch.
The problem with the prior art is that the approaches it describes are really complex and unpractical solutions to the very challenging problem presented here. To illustrate, it may be worth noting that the applicant has not seen a just intonated piano in stores yet. Thus, an unaddressed need for a simplified, and therefore practical, solution to this problem exists. As it will be later described herein, the use of parallel connections between octaves, PLC (i.e., Programmable Logic Controller) and relays, and the use of other simplifying approaches, can overcome the inadequacies and deficiencies of the prior art.
The problems and the associated solutions presented in this section could be or could have been pursued, but they are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches presented in this section qualify as prior art merely by virtue of their presence in this section of the application.